This invention relates to the production of electrical power in large quantitites and more particularly to a powergenerating system and a generating station construction therefor wherein power is stepped up to high line voltages by a rotary mechanism which includes inertial energy storage means for accommodating the cyclical imbalances between energy source output and power utilization demands.
Copending application Ser. No. 505,787 of the present applicant filed Sept. 13, 1974 and entitled ELECTRICAL POWER GENERATION AND DISTRIBUTION SYSTEM discloses a system in which high-voltage electrical energy may be more economically generated and delivered to a city or other powerconsuming site from a number of remote scattered energy sources such as geothermal steam wells, solar energy panels, fuel cells powered from natural gas sources, or others. The system of copending application Ser. No. 505,787 differs from more conventional power production installations by eliminating any need for large costly high-voltage transformers to step up the voltage produced by a generator to the relatively high level carried on the associated cross-country transmission lines. In the system of this copending application, individual stations typically consist of one or more generators mounted on an elevated insulative structure and operated from local primary energy sources through insulative drive means. Owing to the electrical isolation of the generators from ground, successive ones of the stations may be series-connected into a cross-country transmission line without requiring large high-voltage step-up transformers. Each successive component station adds an increment of voltage to the transmission line to build up to the very high voltage which is desirable for cross-country power delivery to a distant utilization site. Such a system makes it economically practical to draw upon scattered, remote, small primary energy sources which cannot be efficiently harnessed by conventional techniques.
Certain types of small primary energy source upon which such a system can potentially draw have the disadvantage of being intermittent. Solar energy cells spread over a land area are, at best, effective only during the daylight hours. Wind-driven generators are subject to the vagaries of meteorological conditions. The demand for power from generating systems usually follows a different cyclical pattern and this complicates the utilization of such energy supplies. Except for this problem, the use of these energy sources has many advantages over reliance on more conventional supplies. Solar energy and wind energy, for example, are essentially inexhaustible in contrast to the fossil fuels widely relied upon at present. Environmental problems are relatively minor. Among other advantages, the best siting of power installations drawing on such sources may be in deserts and other geographical areas which are not extensively utilized for urban, industrial or agricultural purposes.
One technique for reconciling differences in power production cycles and peak power demand cycles is to use energy from the intermittent sources to pump water uphill from a natural body of water or a reservoir to a higher reservoir. The pumped water may then be returned through hydroelectrical facilities as necessary to generate electrical power during periods when the primary sources are inactive or operating at a low level inadequate to meet demand. While this is a satisfactory resolution of the problem in many cases, it requires a suitable geographical site including extensive land areas and sizable water supplies and may be highly costly to construct.
Problems with imbalances between supply and demand due to cyclical factors in power systems are not limited to situations where primary energy sources are intermittent. Power utilization sites such as city utility systems for example typically exhibit sizable demand fluctuations. Designing the power generation system to accommodate to the peak loads requires that much of the system be idle during other periods with consequent adverse effects on efficiency and costs. One technique for alleviating this problem which has heretofore been proposed involves storing excess energy produced during periods of slack demand in large rotating flywheels and then reconverting the stored energy into electrical power during peak-load periods. Such a system is described in an article entitled "Flywheel," by Richard F. Post et al in the publication Scientific American, Volume 229, No. 6, pages 17 to 23, December, 1973. It is therein proposed to couple flywheels to an otherwise conventional generating system through dynamoelectric devices which function as driving motors for the flywheels during periods of reduced power demand and which function as generators during peak demand periods.
While such a system offers many operational advantages, it requires sizable increases in the construction cost of the generation system as a whole. Additional large high-voltage step-up transformers must be added to the system to couple the flywheel stations into the transmission lines and additional large motor-generator devices are needed.
The recovery of energy from scattered small intermittent sources would be more economical and more practical and fluctuations in demand would be more efficiently adjusted to if temporary energy storage capacity can be made available within individual generating stations without requiring large land areas, specialized sites or highly costly supplementary equipment.